1. Field of the Invention
The present invention relates generally to manhole covers, and more specifically, to a manhole security device that prevents access into a manhole by terrorists, vandals or any other unauthorized personnel not having a properly coded access key. Security needs have increased dramatically in recent years and manholes have been used by terrorists to plant bombs in highly trafficked or high profile areas such as parade routes often necessitating the welding shut of manhole covers to prevent the manhole from being breached. Welding the manhole covers shut is time-consuming and deters authorized personnel from doing their job in a quick and efficient manner. The present invention addresses the problem of manhole security by providing a plate that would be placed on the cover-retaining flange in the manhole on which the cover would ordinarily rest. The operator would then insert a coded turnkey through a central recess in the manhole security device until it matched up with it""s corresponding mate on the underside of the plate and then rotate the turnkey thereby extending two locking members in opposing directions until their points are imbedded in the soft metal of the manhole ring. The extended, imbedded locking members below the cover retaining flange prevent the manhole security device from being removed until the properly coded turnkey is inserted and the locking members are retracted. The manhole cover is placed over the locked manhole security device until such time that authorized removal is desired.
2. Description of the Prior Art
There are numerous manhole cover devices, while these devices may be suitable for the purposes for which they were designed, they would not be as suitable for the purposes of the present invention as hereinafter described.
The present invention discloses a plate-like member that would be placed on the cover-retaining flange in the manhole on which the manhole cover would ordinarily rest. The operator would then insert a turnkey through a central recess in the manhole security device until it matched up with its corresponding mate on the underside of the plate and then rotate the turnkey, thereby extending two locking members in opposing directions until their points are imbedded in the soft metal of the manhole ring. The extended, imbedded locking members below the cover retaining flange prevent the manhole security device from being removed until the proper mating turnkey is inserted and the locking members are retracted. The manhole cover is placed over the locked manhole security device until such time that authorized removal is desired.
A primary object of the present invention is to provide a manhole security device that will deny access to unauthorized personnel to the inside of a manhole in which the present invention is deployed.
An additional object of the present invention is to provide a manhole security device that will provide quick and easy access into the manhole by authorized personnel.
A further object of the present invention is to provide a manhole security device wherein the configuration of the male and female interlocking key components can vary to provide additional security.
A yet further object of the present invention is to provide a manhole security device utilizing a double bevel gear mechanism to rotate two opposing shafts to extend the locking members into the manhole ring.
Another object of the present invention is to provide a manhole security device wherein the locking members have a substantially cylindrical body with a first female threaded end and a second sharp, tapered end and further having an anti-rotational flange extending longitudinally from said body.
Still another object of the present invention is to provide a manhole security device wherein each locking member has a corresponding bracket with a keyway through which the locking member passes as the rotatable shaft is threaded or unthreaded thereby retracting or extending said locking member which slides therethrough without rotating due to the anti-rotational flange and the keyway.
Yet another object of the present invention is to provide a manhole security device that is simple and easy to use.
Yet another object of the present invention is to provide a manhole security device that is economical in cost to manufacture.
Further objects of the present invention will appear as the description proceeds.
To the accomplishments of the above and related objects, this invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific construction illustrated and described in the appended claims.